DESCRIPTION: GI peptides are ubiquitous substances, many of which are trophic for epithelial cell growth and development. These peptides modulate their effects after binding to specific receptors. Although there is some cross reactivity, the emergence and characterizations of unique receptors may provide better understanding into control of cellular proliferation. This proposal serves to characterize a unique gastrin associated receptor, G/G-Gly R, which appears to be distinct from the CCK-B receptor in its specificity and action. Better understanding of this receptor and its location, as well as mechanisms for cellular proliferation may allow the use of novel non-toxic forms of anti-neoplastic therapy in GI tract cancers.